Pulse generating device



June 2, 1.959 I v TL E. MYERS 2,889,472

7 v PULSE GENERA'HNG DEVICE Filed Dec. 10, 1957 "2 Sheets-Sheet 1 INVENTOR.

120m E. Myers YYBY ' A TTOENEYS June 2, 1959 T. E. MYERS 1 2,889,472

PULSE GENERATING DEVICE Filed Dec. 10, 1957 2 Sheets-Sheet 2 LOAD INVENTOR.

.- [g5 E. @6119 98 BY 38. 6d 96 v W6Zm A TTORNE Y5 United States Patent Q P 2,889,472 PULSE GENERATING DEVICE Thomas E. Myers, Geneva, Ill. Application December 10, 1957, Serial No. 701,901

11 Claims. 01. 307-132 1 This invention relates to pulse generating devices, and particularly to devices for generating electric pulses at controlled but variable time intervals. The invention comprises a combination of elements operable at very low voltages without using vacuum tubes, transistors, or the like.

In general, the device consists of a first circuit includ ing a load to which pulses are to be applied, a coil-operated relay for periodically closing the load circuit, and delay means associated with the relay to delay release of its armature after de-energization of its coil. The device includes a further relay arranged to open and close the circuit through the coil of the first relay and its own coil. The second relay likewise includes delay means for delaying release of its armature after de-energization of its coil. Both relay delay means include a condenser in parallel with their coils and may further include an associated permanent magnet for providing a constant magnetic field in the relay coils. By adjustment of the position of the magnets relative to the coils, the delay time of the relay may be varied within very wide limits. With the apparatus of this invention a wide range of adjustments is possible wherein the time duration of each pulse and the time between pulses may be predetermined. The invention also contemplates the use of relays without magnets, in a novel circuit, permitting construction of a highly accurate, dependable and inexpensive pulse generator operating at predetermined fixed time intervals.

In the following description and claims, reference to a coil-actuated relay is intended to refer to a relay having a coil which, when energized, attracts an armature to open or close contacts in an external circuit. The term normally open relay is employed to refer to such a relay wherein a spring or the like normally holds the armature in position to hold the contacts of the external circuit apart or in open condition, and the term normally closed refers to such a relay wherein the spring or similar device holds the contacts of the controlled external circuit in contact or in closed condition.

There are many instances wherein it is desired to accurately control the duration and frequency of electrical pulses and wherein it is desired to control such pulses with low voltage batteries without employing complicated circuits or vacuum tubes. Such a device finds utility in controlling blinker lights, beacons and flashers of all types, in addition to having utility in telemetering equipment and, in fact, any installation where controlled pulses are desired.

It is therefore an object of this invention to provide an electric pulse generator that is simple in construction, economical to produce, and eflicient and reliable in operation. Y Another object of the invention is to provide such a pulse generator having a wide range of adjustment without replacing or interchanging parts thereof.

. Still another object of the invention is to provide a pulse generator operable at low voltage and without resorting to vacuum tubes or the like.

A further object of the invention is to provide a pulse Another and further object of the invention is to pro-.

vide a novel time delay relay.

Additional objects and advantages will become apparent to those skilled in the art as the description proceeds with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic circuit diagram illustrating a preferred form of the invention;

Fig. 2 is a schematic circuit diagram illustrating a second embodiment of the invention;

Fig. 3 is a schematic illustration of a pair of relays for use in the device of the present invention and illustrating a common permanent magnet for both relays;

Figs. 4 and 5 illustrate further modifications of the invention as embodied in Figs. 1 and 2; and

Figs. 6 and 7 are diagrammatic illustrations of further embodiments of the invention represented by Figs. 1 and 2.

In all of the embodiments illustrated, the relays shown for purpose of illustration have certain common features. For instance, each relay comprises an electromagnetic coil 2 mounted on a suitably formed pole piece 4. Each pole piece 4 is provided with a leg outside the coil 2 and on the end of which an armature 6 is pivotally mounted. in each relay a spring '8 or equivalent device biases the armature 6 to normally occupy a position outwardly of the end of the pole piece 4 projecting from the coil 2. In such relays, as is common, energization of the 'coil 2 attracts the extending portion of armature 6 toward the coil against the action of spring 8. The armatures 6 carry suitable contacts cooperating with fixed contacts to open or close an external circuit. I

Referring now specifically to Fig. l, a load device 10 is schematically shown and may comprise any desired device to be actuated by electrical pulses. For instance, the load device may be a flasher, light, or the like.

The load device 10 is in a circuit comprising conductors 12, 14, 16, battery 18, conductors 20, 22 and 24. The conductors 22 and 24 are connected to contacts 26 and 28, respectively, of relay B. The contact 26 is carried by the armature 6 of relay B and contact 28 is a fixed contact. As shown, the spring 8 of relay B holds the contacts 26 and 28 normally apart and the relay B will be referred to as a normally open relay. A starting switch 30 is provided between conductors 14 and 16.

Relay A is a normally closed relay since its spring 3 normally holds armature contact 32 in engagement with fixed contact 34. Fixed contact 34 is electrically connected to the junction of conductors 12 and 14, whereas contact 32 is electrically connected to one end of coil 2. of relay A, through conductors 36 and 38. The junction between conductors 36 and 38 is electrically connected, through conductor 40, to one plate of a condenser 42. The other plate of condenser 42 is electrical ly connected, through conductors 44 and 46, to one plate of condenser 48 of relay B and the other end of coil 2 of relay A is connected, by means of a conductor 50, to conductor 46. One end of coil 2 of relay B is connectecl through conductor 52 to the conductor 46. The other plate of condenser 48 is connected by conductor 54- to the conductor 26, previously described. The other end of coil 2 of relay B is connected by conductor 56 to conductor 54.

As is apparent, the condenser 42 is connected in parallel with the coil 2 of relay A and condenser 48 is connected in parallel with the coil 2 of relay B.

As previously stated, relay A is normally closed and relay B is normally open. Therefore, when starting switch 30 is closed, current from the battery 18 flows through Patented June 2, 1959 lcoil, produced by the associated magnet 66.

3 conductors 16, 14, 12, load and conductor 24 to the contact 28. At the same time current flows through contacts 32 and 34, conductors 36 and 38, coil 2 of relay A, conductors 50, 46 and 52, coil 2 of relay B, and conductors 56, 54 and 20,- which define a circuit complete through the battery 18. At the same time the condensers 42 and 48, in parallel with their respective coils, are changed. As soon as current flows through the coils 2, the respective relay armatures are actuated to separate contacts 32 and 34 and simultaneously close contacts 26 and 28. As soon as contacts 26 and 23 are closed, a circuit is completed through the battery 18 and load 16 to apply an electrical pulse to the load. However, as soon as the coils 2 are energized, contacts 32 and 34 separate to disconnect both coils 2 from battery 18. Contacts 26 and 28, however, do not immediately separate since the charge on condenser 48 is then discharged through the coil 2 of relay B to maintain that coil energized until the condenser 48 is completely discharged. (Jondenser 48 thus delays release of the armature 6 of relay B for a predetermined period of time, depending on the capacity of the condenser 43. That period of delay determines the duration of the pulse applied to the load 10. Condenser 42 is of substantially greater capacity than condenser 48 and will stait to discharge at the same time condenser 48 starts to discharge, as described above. However, since condenser 42 has greater capacity than condenser 48, it will maintain its associated coil 2 energized for a longer period of time and will delay release of its armature 6 until a time subsequent to the release of the armature 6 of relay B. Therefore, after the pulse has been applied to the load 10, as described, and con tacts 126 and 28 opened by spring 8, contacts 32 and 34 will remain open for a continu ng period and until condenser 42 of relay A is completely discharged. Thereafter spring 8 returns contacts 32 and 34 to closed condition and the above-described cycle is repeated to apply a subsequent pulse to the load 10.

From the above description it can be seen that the delay period of relay B determines the duration of the pulse, Whereas the delay period of relay A determines the time between pulses or cycle time.

Applicant has discovered that the time delay interval of each of the relays A and B can be changed, withbut changing the capacity of either condenser 42 or 48 by the use of a permanent magnet or equivalent device. As shown, each of the relays A and B includes a bracket 60 having a slotted arm that may be clamped, by means of wing nuts 62, to the pole base 4. The other leg of each bracket 60 is provided with a spring clip 64 removably supporting a permanent magnet 66. Preferably, each bracket 60 is provided with a fine adjusting screw 68. With the structure thus described, the wing nut 62 may be loosened and the adjusting screw 68 manipulated to move the magnet 66 closer to or farther from its as- 'sociated coil 2 and the wing nut then tightened. Further, either magnet 66 may be removed from its spring clip 64 and reversed to reverse the position of its poles.

Even when the coils 2 are de-energized, a portion of the magnetic field created by each permanent magnet 66 permeates the pole piece 4 extending through the associated coil 2 and thus a portion of the magnetic field extends through the coil 2. During these time intervals when condenser 42 or condenser 48 is discharging through its associated coil 2, the rate of discharge is dependent on the intensity of the magnetic field in that Thus, with a magnet 66 in such position that its field accelerates discharge of the associated condenser, the normal time interval is decreased. If the magnet is reversed so that its field bucks or opposes discharge of the condenser, the time delay interval of the relay is thus increased beyond its normal value. In like manner adjustment of either magnet 66 toward or from its associated coil 2 will change 4 the intensity of the field thereof in the coil and thus vary or change the time delay interval of that relay.

In a circuit as described in connection with Fig. 1, it has been found that by employing coils 2 of 100 ohms resistance and a battery 18 of 6 volts with condenser 48 having a capacity, at that voltage, of 200 mfd. and with condenser 42 having a capacity of 2,000 mfd, time duration of the pulse can be varied or changed from a minimum of 10 milliseconds to a maximum of 2 seconds and that the total cycling time (the time interval between the start of one pulse and the start of a subsequent pulse) can be changed from a minimum of onequarter of a second to a maximum of 10 seconds by mere manipulation of the magnets 66 in the manner described. The time delay interval of each relay was found to vary inversely as the square of the distance between the magnet and its associated coil. As is obvious, a change in the capacity of the condenser effects a linear change in the time delay period, whereas a change in the applied voltage produces no appreciable change in time.

In the embodiment of Fig. 2, the relays A and B are identical to the relays A and B of Fig. 1, except that the contacts associated with their respective armatures are arranged somewhat differently. The relay A, however, is normally closed and the relay B is normally open. Relay A is provided with a relatively large contact 70 on its armature 6 and has two fixed contacts 72 and 74. The contacts 72 and 74 must be arranged so that 72 is the first one engaged by contact 70 as the relay closes. Those parts of Fig. 2 that are identical to corresponding parts of Fig. l bear the same reference numerals. The contact 74 of relay A is connected, through conductor 76 to the parallel-connected condenser 42 and coil 2 of that relay and then through conductors 78 and S8 to starting switch 30 and battery 18. The other side of battery 18 is connected through conductors 82 and 84 to the contact 70 on armature 6 of relay A. The fixed contact 72 of relay A is connected through conductor 86 to the parallel-connected condenser 48 and coil 2 of relay B and then through conductors 88, 90, 80, and switch 30 to the first side of battery 18. The junction between conductors 82 and 84 is connected by conductor 92 to the load 10 and the other side of the load is connected by conductor 94 to the armature contact 96 of relay B. Fixed contact 98 of relay B is connected through conductor 100 to the junction between conductors 88 and 90.

The circuit thus described functions similarly to that of Fig. 1. When the starting switch 30 is closed, a circ'uit is completed from one side of battery 18 through conductors and 78 through the parallel-connected condenser 42 and coil 2 of relay A, then through conductor 76, contact 74, contact '70, and conductors 84 and 82 to the other side of the battery. At the same time a circuit is completed from the battery 18 through switch 30, conductors 80, and 88 through the parallel-connected condenser 48 and coil 2 of relay B, then through conductor 86, contacts 72 and 70, and conductors 84 and 82 to the other side of battery 18. Thus, both relay coils are simultaneously energized upon closing switch 30. As soon as those coils are energized, relay B closes and completes a circuit through the battery and load 10. The battery thus delivers a pulse to the load circuit. As soon as coil 2 of relay A is energized, however, its condenser 42 is charged and armature 6 is drawn downwardly to break connection between its contact 70 and fixed contacts 72 and 74. 7 Thus, the power circuit through the coil 2 and condenser 42 is broken. However, the discharging of condenser 42 through the coil 2 of relay A, as delayed by magnet 66, results in holding the contact 70 its downward or open position for a predetermined period of time." Likewise, as soon as the relay A is opened (upon closing starting switch 30) the circuit through the coil 2 and condenser 48 of relay B is opened, by separation of contacts 70 and 72. The armture'fi of relay B, however, does not return to its normally open position immediately because themagnetic lfield of its coil 2 is maintained by the previously described dis-. Charging of condenser 48 and the time of such discharge is controlled by the adjustment of its associated magnet 66. In the form of Fig. 2 also the condenser 42 is of much greater capacity than the condenser 48. As described, as soon as starting switch 30 is closed, the relay A is opened and relay B is closed. Upon opening of relay A, the circuit through battery 18 and both coils 2 is broken with current being delivered to the load. Condenser 48 will discharge first, however, being of lower capacity, to break the circuit through the load and after the elapse of a further interval of time condenser 48 becomes fully discharged and relay A closes and the above-described cycle is repeated.

Fig. 3 illustrates a further form of relays employing a single permanent magnet 102 serving the coils 2 of both relays A" and B". In this form the relays A and B are mounted on a supporting base 104 in relatively close proximity to each other. The base 104 is provided with a wide slot 106 therethrough in the region between the relays. The magnet 102 is removably supported in a suitable spring clip 108 on bracket 110 having a base 112. A clamp screw 114 passes through the base 112 and slot 106. A suitable wing nut 1 16 or the like serves to clamp the base 112 and its bracket 110 in any desired position of adjustment on the supporting plate 104. Preferably the slot 106 is considerably wider than the diameter of the shank of screw 114 so that the magnet 102 may be adjusted either to the right or left, as seen in Fig. 3, or in a direction perpendicular to the plane of the drawing. By using the structure of Fig. 3 the single magnet serves to regulate the time interval of both relays simultaneously. As is obvious, the magnet 102 may be adjusted closer to one relay and farther from the other, or, within limits, may be moved farther from one relay while maintaining a fixed distance from the center of the coil 2 of the other relay.

, As shown, the relay B" is adjustably mounted on the base 104 by means of bolt 105 and wing nut 107, the bolt 11S passing through a slot 109 in base 104. By adjustably mounting the relay B", as described, a greater range of adjustments is permitted.

The relay structure of Fig. 3 may be employed with any of the circuits shown in Figs. 1, 2, 6 or 7, it being only necessary to provide the relays with the. contact arrangements shown in the selected figure.

The structure of the relays of Figs. 1, 2 and 3, and the other figures to be described, and the means shown for adjusting the permanent magnets 66 and 102 are merely illustrative, it being understood that other structural arrangements and adjusting means may be resorted to within the scope of this invention. For example, in telemetering or similar applications, the magnets could be adjusted automatically by a variable function.

The use of permanent magnets, specifically, is not essential since equivalent regulating means could be in the form of an electromagnetic coil physically adjustable relative to the relay coil or a fixed electromagnetic coil having means for changing and/or reversing the flow of current therethrough.

While Figs. 1, 2 and 3 illustrate embodiments wherein the magnets and coils are relatively adjustable, it is within the scope of this invention to mount the magnets in fixed position relative to their respective coils. Such a construction would result in a non-adjustable circuit but would still permit constructing a pulse generating device having relatively long time periods between pulses and relatively long pulses without necessitating the employment of large, expensive condensers. In other words, by the employment of inexpensive fixed magnets and inexpensive, relatively low-capacity condensers, a pulse generator may be designed and constructed having longer time intervals than would be possible without the magnets, except by using large, expensive condensers.

Referring now to Figs. 4 and 5, the circuits shown therein are identical to the circuits shown in Figs. 1 and 2, respectively, except that the relays are illustrated without associated magnets, either fixed or adjustable. The circuits of Figs. 4 and 5 operate in exactly the same manner as described in connection with Figs. 1 and 2, respectively. In these modifications, however, the time interval between pulses and the duration of each pulse is determined solely by the capacity of the respective condensers 42 and 48.

Figs. 6 and 7 correspond generally to Figs. 1 and 2. and like elements therein are indicated by the same reference numerals. In Fig. 6, however, the relays are identiiied as R and R The relays R and R may have associated therewith either fixed or adjustable magnets or they may be relays having no magnets associated therewith. In Figs. 1 through 5, the battery 18 supplies the power for operating the load 10. In Figs. 6 and 7, on the other hand, the battery supplies only the direct current for operating the relays while the load 10 is supplied with current from a difierent source. a

For example, in Fig. 6, the battery 18 supplies the direct current for operating the relays R and R andthe operation thereof is exactly the same as already described in connection with Figs. 1 and 2. However, the conductors 12 and 22 of Fig. 1 have been omitted. In Fig. 6, the contact 28 of relay R is connected by conductor 24 to one side of the load 10. The other side or load 10 is connected through conductor 115 to a suitable terminal 116. The movable contact 26 of relay R is connected by conductor 118 to a second terminal 120. As will be obvious, the relays R and R operate in the same manner as described in connection with Fig. l to periodically open and close contacts 26 and 28. The contacts 26 and 28 alternately complete and open a circuit through the load 10 and terminals 116 and 120. The terminals116 and 120 may, therefore, be connected to any desired source of power for the load 10. In other words, the load 10 may be operated by alternating current of any desired voltage or frequency or may be operated by direct current at a different voltage from that obtainable from the battery 18. The modification of Fig. 6, therefore, adapts the invention to a wide variety of load devices, many of which would not be operable by current from the battery 18.

The circuit shown in Fig. 7 corresponds to that of Figs. 2 and 5 but, here again, the battery 18 is employed to operate only the relays R and R As was described in connection with Fig. 6, the relays R and R of Fig. 7 may have adjustable magnets associated therewith or they may have fixed magnets associated therewith. On the other hand, they may have relays without magnets, as illustrated in Figs. 4 and 5. In the modification of Fig. 7, the conductors 92, 94 and of Figs. 2 and 5 are eliminated, thus separating the load 10 from battery 18. The battery 18 thus supplies current only for the operation of the relays R and R in the manner previously described. Contacts 96 and 98 of relay R are respectively connected, through conductors 122 and 124, to terminal 120 and one side of load 10. The other side of load 10 is connected by conductor to a terminal 116. The terminals 116 and 120, as in the case of the Fig. 6 embodiment, may be connected to any desired source of power other than battery 18 for the same reasons as set forth in describing Fig. 6. Fig. 7, therefore, is a circuit corresponding generally to that of Figs. 2 and 5 but wherein relay R alternately opens and closes an external circuit through the load and a source of power other than the battery 18. The advantages of this circuit over that of Figs. 2 and 5 are the same as the advantages described in connection with Fig. 6.

It is to be understood that in all embodiments shown in Figs. 1, 2, 6 and 7, wherein it is desired to use mag- 7 nets in association with the relays, a single magnet may be employed for both relays in the manner suggested in Fig. 3.

While a limited number of embodiments of the invention have been diagrammatically shown and described, the circuits and structure thus described are merely illustrative of the invention which encompasses other forms and modifications falling fairly within the scope of the appended claims.

I claim:

1. In a pulse generating device, a first normally open coil-operated relay for closing a circuit through a load device when energized, a second normally closed coiloperated relay for opening a circuit to de-energize the coils of both said relays, each of said relays including delay means for delaying decay of the magnetic field of its coil after de-energization of said coil.

' 2. A pulse generating device as defined in claim 1 wherein each of said delay means comprises a condenser in parallel with its associated coil.

3. A pulse generating device as defined in claim 1 including magnet means adjacent the coils of said relays whereby to provide a constant magnetic field through said coils.

4. A pulse generating device as defined in claim 1 including a permanent magnet adjacent the coil of each relay whereby to provide a constant magnetic field through said coil, each of said magnets being adjustable relative to its associated coil to change the intensity of said constant magnetic field in said coil and thereby change the decay time provided by said delay means.

5. A pulse generating device as defined in claim 1 wherein each of said delay means comprises a condenser in parallel with its associated coil, and a permanent magnet adjacent the coil of each relay to provide a constant magnetic field through its associated coil.

6. A pulse generating device as defined in claim 5 wherein said magnet is reversibly mounted whereby to reverse the direction of said constant field in said coil.

7. In a pulse generating device, a first normally open coil-operated relay for closing a circuit through a load device when energized, a second normally closed coiloperated relay for opening a circuit to disconnect the coils of both said relays from a source of power, each of said relays including delay means for delaying decay of the magnetic field of its coil after said disconnection of said coil, each of said delay means comprising a condenser in parallel with its associated coil and regulating means for creating a constant magnetic field through said coil.

8. A pulse generating device as defined in claim 7 wherein said regulating means is adjustable to selectively change the intensity of said constant magnetic field.

9. A pulse generating device as defined in claim 8 wherein said regulating means is adjustable to selectively reverse the direction of said constant magnetic field through said coil.

10. In a pulse generating device, a load circuit, a source of current in said load circuit, a first normally open coil-operated relay for closing said load circuit, a second normally closed coil-operated relay for opening a circuit from a source of current through said coils, each of said relays including delay means for delaying decay of the magnetic field of its coil after opening the circuit therethrough, said delay means associated with said second relay being effective to produce a longer period of delay than the delay means of said first relay.

11. In a time delay relay, an actuating coil having a condenser connected in parallel therewith, a permanent magnet, and means mounting said permanent magnet adjacent said coil in such a position that at least a portion of the magnetic field of said permanent magnet passes through said coil, said mounting means being adjustable to move said magnet relative to said coil to vary the intensity of said magnetic field in said coil.

References Cited in the file of this patent UNITED STATES PATENTS 2,430,457 Diamond Dec. 11, 1947 

